Lose/restore WebGL contexts if multisampling blackist status changes at runtime.

Source/core/page/Settings.h

 /*
  * Copyright (C) 2003, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 142 matching lines @@
 
     static void setMockScrollbarsEnabled(bool flag);
     static bool mockScrollbarsEnabled();
 
     static void setUsesOverlayScrollbars(bool flag);
     static bool usesOverlayScrollbars();
 
     void setTouchEventEmulationEnabled(bool enabled) { m_touchEventEmulationEnabled = enabled; }
     bool isTouchEventEmulationEnabled() const { return m_touchEventEmulationEnabled; }
 
+    void setOpenGLMultisamplingEnabled(bool flag);
+    bool openGLMultisamplingEnabled();
+
 private:
     explicit Settings(Page*);
 
     void initializeDefaultFontFamilies();
 
     Page* m_page;
 
     String m_mediaTypeOverride;
     KURL m_userStyleSheetLocation;
     ScriptFontFamilyMap m_standardFontFamilyMap;
@@ skipping 15 matching lines @@
     bool m_areImagesEnabled : 1;
     bool m_arePluginsEnabled : 1;
     bool m_isScriptEnabled : 1;
     unsigned m_fontRenderingMode : 1;
     bool m_isCSSCustomFilterEnabled : 1;
     bool m_cssStickyPositionEnabled : 1;
     bool m_cssVariablesEnabled : 1;
     bool m_dnsPrefetchingEnabled : 1;
 
     bool m_touchEventEmulationEnabled : 1;
+    bool m_openGLMultisamplingEnabled : 1;
 
     Timer<Settings> m_setImageLoadingSettingsTimer;
     void imageLoadingSettingsTimerFired(Timer<Settings>*);
 
     static bool gMockScrollbarsEnabled;
     static bool gUsesOverlayScrollbars;
 };
 
 } // namespace WebCore
 
 #endif // Settings_h